It is advantageous to manufacture the ropes of lifting devices, more particularly the hoisting ropes and suspension ropes of passenger transport and freight transport elevators, to be of a composite structure. When basing the longitudinal load-bearing capability of ropes on non-metallic material, more particularly on non-metallic reinforcing fibers, the ropes can be lightened and as a result of the roping being lightweight the energy efficiency of the elevator can be improved. By forming the rope to be composite-structured and belt-type, considerable savings can be achieved even though the inexpensive metal material conventionally used in the ropes of an elevator is replaced with more expensive material.
A travelling cable is fixed to the car of a passenger transport elevator and/or freight transport elevator, via which travelling cable the elevator car is in connection with the elevator control center. The travelling cable is generally round in shape or is a flat cable and comprises electrical conductors and a load-carrying bearer surrounded by a protective envelope. The travelling cable is used for power transmission and with it the necessary electrical energy is supplied to the elevator car and with it data is transmitted between the signaling devices of the elevator car, such as car call pushbuttons, communication devices and displays, and also the control system of the elevator. The load-bearing part of the travelling cable is according to prior art a steel rope bearer, typically a 6-strand or 8-strand steel rope, which comprises a steel core and strands passing around it. The travelling cable is typically fixed at the first end of the rope bearer to the elevator car and at the second end to the elevator hoistway.
The travelling cable can also be used fully or partly as compensation to compensate the moment of imbalance caused by the hoisting ropes, which moment of imbalance is created when the car moves. When using composite-structured lightweight hoisting ropes and suspension ropes, the mass per meter of travelling cables implemented with steel rope bearers is too great for implementing optimal compensation. Travelling cables comprising steel rope bearers are too heavy for use with lightweight composite ropes, in which case overcompensation of the ropes becomes a problem.
Additionally, a problem particularly in high-rise buildings and in the high-speed elevators used in them is that at high speeds vortices occur in the elevator hoistway owing to the air resistance of the elevator car, which vortices produce lateral movement in the travelling cable of the elevator and more particularly in the bottom loop of said cable. Sideways movement in the lateral direction of the travelling cable in high-rise buildings is also caused by movements of the elevator car itself and from swaying of the building caused mainly by wind. This type of lateral swaying is undesirable, because it increases the stressing of the travelling cable and produces noise and vibration or other discomfort to passengers of the elevator car. In addition, large lateral movement might cause the travelling cable to strike structures of the elevator hoistway, damaging hoistway devices or itself getting caught on them. In this case one consequence can even be an emergency stop of the elevator. Known in the art are sway damping solutions wherein the travelling cable of the elevator is guided with various guides to travel along a certain path or a separate damping means is used in the bottom loop of the travelling cable.